Acoustic and hydrodynamic cavitation assisted hydrolysis and valorisation of waste human hair for the enrichment of amino acids.

Hair waste in large amount is produced in India from temples and saloons, India alone exported approximately 1 million kg of hair in 2010. Incineration and degradation of waste human hair leads to environmental concerns. The hydrothermal process is a conventional method for the production of hair hydrolysate. The hydrothermal process is carried out at a very high temperature and pressure, which causes the degradation of heat-sensitive essential amino acids, thereby depleting the nutritional value. This work deals with alkaline hydrolysis of human hair using acoustic and hydrodynamic cavitation, and comparison with the conventional method. The optimal operating conditions for highest efficiency was observed, for the hydrolysis of 1 g of sample hairs in 100 mL of solution, at 4:1 (KOH: hair) ratio, soaking time of 24 h, the ultrasonic power density of 600 W dm-3 (20 KHz frequency and input power 200 W) or hydrodynamic cavitation inlet pressure of 4 or 7 bars. Cavitation results in rupture of disulfide linkages in proteins and mechanical effects lead to cleavage of several hydrogen bonds breaking the keratin sheet structure in hair. Breakdown of bonds leads to a decrease in viscosity of the solution. 10% and 6% reduction in viscosity is obtained at optimal conditions for ultrasonic and hydrodynamic cavitation treatment, respectively. FTIR analysis of produced hair hydrolysate confirmed that the disulfide bonds in hair proteins are broken down during cavitation. The amino acid of hair hydrolysate, prepared using cavitation, has a relatively higher digestibility and nutritional value due to the enhancement of amino-acid content, confirmed using amino acid analysis. Cavitation assisted hair hydrolysate has a potential application in agricultural engineering as a fertilizer for improvement of the quality of the soil and land. Cavitation based hair hydrolysate can also be used as an environmentally friendly and economical source of essential amino acids and digestibles for animal or poultry feed.

A critical review on textile wastewater treatments: Possible approaches.

Waste water is a major environmental impediment for the growth of the textile industry besides the other minor issues like solid waste and resource waste management. Textile industry uses many kinds of synthetic dyes and discharge large amounts of highly colored wastewater as the uptake of these dyes by fabrics is very poor. This highly colored textile wastewater severely affects photosynthetic function in plant. It also has an impact on aquatic life due to low light penetration and oxygen consumption. It may also be lethal to certain forms of marine life due to the occurrence of component metals and chlorine present in the synthetic dyes. So, this textile wastewater must be treated before their discharge. In this article, different treatment methods to treat the textile wastewater have been presented along with cost per unit volume of treated water. Treatment methods discussed in this paper involve oxidation methods (cavitation, photocatalytic oxidation, ozone, H2O2, fentons process), physical methods (adsorption and filtration), biological methods (fungi, algae, bacteria, microbial fuel cell). This review article will also recommend the possible remedial measures to treat different types of effluent generated from each textile operation.

Kinetics of biological decolorisation of anthraquinone based Reactive Blue 19 using an isolated strain of Enterobacter sp.F NCIM 5545.

In the present study, an attempt was made to evaluate the bacterial decolorisation of Reactive Blue 19 by an Enterobacter sp.F which was isolated from a mixed culture from anaerobic digester for biogas production. Phenotypic characterization and phylogenetic analysis based on DNA sequencing comparisons indicate that Enterobacter sp.F was 99.7% similar to Enterobacter cloacae ATCC13047. The kinetics of Reactive Blue 19 dye decolorisation by bacterium had been estimated. Effects of substrate concentration, oxygen, temperature, pH, glucose and glucose to microbe weight ratio on the rate of decolorisation were investigated to understand key factor that determines the performance of dye decolorisation. The maximum decolorisation efficiency of Reactive Blue 19 was 90% over period of 24 h for optimized parameter. To the best of our knowledge, this research study is the report where Enterobacter sp.F has been reported with about 90% decolorizing ability against anthraquinone based Reactive Blue 19 dye.